The present invention relates to product transferring systems and more specifically to transferring a discrete number of baked goods such as crackers from a first conveyor to a second conveyor or cross conveyor that is traveling in a generally different direction wherein both the product and the mechanism that conveys the product are in continuous motion.
With today's modern high-speed packaging technology, many products require the rearranging or reorientation of the product as it is being conveyed. This can be due to an automated dispensing machine that initially positions a product with one orientation while a subsequent operation requires that the product be received with a different orientation. This is especially troublesome for the food industry and most specifically for mechanical handlers of cookies, crackers, baked goods and the like that will be automatically wrapped while on edge to create packages.
After crackers exit an oven, they are eventually organized into horizontally oriented groups on edge in which each group has a finite number of crackers. To begin orienting the groups for packaging, the groups, known in the art as slugs, are usually then dispensed onto a first conveyor traveling in a first direction. Because of the requirements of the automated dispensing machine, the groups or slugs are oriented with their longest length being perpendicular to the direction of movement of the first conveyor. Thus, after dispensing, the cookie or cracker edges are oriented in the first direction of travel on the first conveyor.
After entry on or into the first conveyor, the groups or slugs proceed through the first conveyor to the remainder of the conveyor system towards a wrapping machine. Due to the requirements of the wrapping machine, the direction of orientation of the groups must be changed by 90 degrees to allow the slugs to enter the packaging machine lengthwise. This requires the direction of travel of the slugs to be changed from the first orientation where their lengthwise direction is perpendicular to the movement of a conveyor to a second orientation where their lengthwise direction is parallel to the direction of movement on the conveyor. In the second direction, the faces of the crackers are oriented in the direction of travel.
In order to achieve the desired result of reorienting the groups by 90 degrees, prior art designs align two conveyors orthogonal to one another. The first conveyor receives the slugs of crackers with their lengths extending perpendicular to the direction of movement of the conveyor. The first conveyor transports the slugs from a slug forming/dispensing machine or mechanism at the beginning of the first conveyor to a second conveyor positioned at the end of travel of the first conveyor. The second conveyor, called a cross conveyor, is continuously moving in a direction that is 90 degrees to the movement of the first conveyor. Various techniques and features are used in the prior art to transfer the slugs from the first conveyor to the cross conveyor. In one of its simplest forms, the transfer technique involves a reciprocating mechanism that slides each slug in turn from the first conveyor to the second conveyor which results in changing the direction of the slugs. Problems with existing systems at higher speeds include damage to the crackers caused by an abrupt change in direction of travel and the physical limitations of the reciprocating mechanism that transfers the slugs from the first conveyor to the second conveyor due to the inertial forces involved.
Thus, the slug on the first conveyor may be visualized as moving at a speed S along an X-direction and a speed 0 in the Y-direction. Upon reaching the cross conveyor, the slugs change velocity so as to move at a speed of 0 in the X-direction and at a speed of T in the Y-direction. Practically, this results in the slug remaining still for a certain moment of time as they are transferred between the two conveyors. The rate at which crackers may be moved from a dispensing automated machine to an automated wrapping machine is limited by the brief stopping of the crackers as they change direction.
Those familiar with the art of transporting cookies and crackers on edge know that the product must be constrained or confined in a predictable and orderly way during the transporting from an oven where the product lays flat and to the final wrapping where the product is on edge. In the current method of moving product through the first conveyor, the first conveyor has moving flight bars along both long sides of the slugs. The flight bars confine and transport the slugs and keep the slugs separated from each other at a predetermined pitch or distance. Usually, fixed guides in current first conveyors keep the crackers in line and from falling over at either short end of the slugs. The first conveyor is usually fed or supplied with slugs by upstream dispensing machinery or, occasionally, by hand.
Currently, cross conveyors, also called in-feed conveyors or in-feed sections because the in-feed is an integral part of the machine that does the wrapping downstream, use moving pins at both short ends of the slugs to transport the slugs and to keep the end of each slug upright. The moving pins at the front and rear ends of each slug also set the pitch or distance between slugs. Fixed side guides or guide rails along both long edges of the slug keep the crackers in line along the sides of the slug as the slugs are transported by the pins. During normal operation, the pins of the cross conveyor move the slugs at a constant speed so as to accommodate the operations downstream. However, since the downstream wrapping operation is not flawless and for this reason and for other reasons that are not germane, automatic electronic means are usually provided to sometimes slow down or stop the wrapping operation and correspondingly slow or stop the cross and first conveyors as well as the product being fed to the first conveyor.
There is an opening in one of the side rails of the cross conveyor of current equipment where the first conveyor abuts the cross conveyor. The opening in the side rail of the cross conveyor is where reciprocating machine mechanisms transfer a slug from the first conveyor to the space between the moving pin arrangement of the cross conveyor. The reciprocating transfer mechanism pushes the slug, on the long side, in between the moving pins of the cross conveyor where the second of the two pins then pushes the slug on a short side in a perpendicular direction to the direction in which the slug had been moving before transfer. The timing of the transfer from the first conveyor to the cross conveyor is critical since the slug must be pushed into position between two pins at the same moment that the moving pins are passing the location where the slug will be received. The distance between pins is only slightly more than the length of the incoming slug. As a consequence of the right angle change in direction of travel of the slug, the slug's movement is stopped for a brief moment. The brief stop or intermittent motion of the slug and, of course, the intermittent motion of the mechanism that transfers the slug from a transverse moving direction to an in-line moving direction, establishes a practical, maximum transfer speed. Intermittent motion can be imagined by envisioning a non-stop train moving through a passenger station with a door open and a passenger on the platform running across the platform toward the moving train at a right angle and jumping through the open door in order to board the moving train. The time interval for transfer and change of direction is short and must be precise for both the slug in existing machines and the passenger in the train analogy.
Some increase in speed is accrued in current machines by including a mechanism in the cross conveyor to withdraw the first moving pin that would be in front of the slug before the moment of slug transfer from the first conveyor to the cross conveyor and then immediately restoring the front pin as soon as the slug transfer is complete. In the industry, the hardware devices that are in front of and in back of each slug in the cross conveyor are commonly called pins, although, they are in practice, all manner of configurations including custom shape castings.
The narrow window of time available for transfer of slugs associated with the abrupt change in direction of motion of the slug and possibly the normal variation in the size of slugs, results in a high rate of product breakage in existing machinery.